<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .container {
            width: 450px;
            height: 450px;
            display: flex;
        }
        .box {
            flex:1;
            text-align: center;
            line-height: 450px;
            background-color: green;
        }
        .box:nth-child(odd) {
            background-color: blue;
        }
        .item1 {
            order: 99;
            flex-basis: 150px;
            width: 100px;
        }
        .item2 {
            order: -1;
        }
        .item3 {
            order: -2;
        }
    </style>
</head>
<body>
    <div class="container">
        <div class="box item1">item1</div>
        <div class="box item2">item2</div>
        <div class="box item3">item3</div>
        <div class="box item4">item4</div>
        <div class="box item5">item5</div>
    </div>
</body>
</html>